Recommendations for fluoride limits in drinking water based on estimated daily fluoride intake in the Upper East Region, Ghana.

Dental fluorosis occurs in parts of northern Ghana from high fluoride drinking water.

High water consumption in this hot climate results in increased fluoride intake.

Result is dental fluorosis in areas with fluoride in water below 1.5 mg/L WHO limit.

Recommendation is lower limit for fluoride in drinking water in hot climates.

Children under six years need lower limit for fluoride in drinking water than adults.

Both dental and skeletal fluorosis caused by high fluoride intake are serious public health concerns around the world. Fluorosis is particularly pronounced in developing countries where elevated concentrations of naturally occurring fluoride are present in the drinking water, which is the primary route of exposure. The World Health Organization recommended limit of fluoride in drinking water is 1.5 mg F– L -1, which is also the upper limit for fluoride in drinking water for several other countries such as Canada, China, India, Australia, and the European Union. In the United States the enforceable limit is much higher at 4 mg F– L -1, which is intended to prevent severe skeletal fluorosis but does not protect against dental fluorosis. Many countries, including the United States, also have notably lower unenforced recommended limits to protect against dental fluorosis. One consideration in determining the optimum fluoride concentration in drinking water is daily water intake, which can be high in hot climates such as in northern Ghana. The results of this study show that average water intake is about two times higher in Ghana than in more temperate climates and, as a result, the fluoride intake is higher. The results also indicate that to protect the Ghanaian population against dental fluorosis, the maximum concentration of fluoride in drinking water for children under 6–8 years should be 0.6 mg F– L -1 (and lower in the first two years of life), and the limit for older children and adults should be 1.0 mg F– L -1. However, when considering that water treatment is not cost-free, the most widely recommended limit of 1.5 mg F– L -1 – which is currently the limit in Ghana – may be appropriate for older children and adults since they are not vulnerable to dental fluorosis once the tooth enamel is formed.